This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -9 |
| 2 | 1 |
| 3 | 90 |
| 4 | -19 |
| 5 | 1 |
| 6 | -990 |
| 7 | 299 |
| 8 | -30 |
| 9 | 1 |
| 10 | 11880 |
| 11 | -4578 |
| 12 | 659 |
| 13 | -42 |
| 14 | 1 |
| 15 | -154440 |
| 16 | 71394 |
| 17 | -13145 |
| 18 | 1205 |
| 19 | -55 |
| 20 | 1 |
| 21 | 2162160 |
| 22 | -1153956 |
| 23 | 255424 |
| 24 | -30015 |
| 25 | 1975 |
| 26 | -69 |
| 27 | 1 |
| 28 | -32432400 |
| 29 | 19471500 |
| 30 | -4985316 |
| 31 | 705649 |
| 32 | -59640 |
| 33 | 3010 |
| 34 | -84 |
| 35 | 1 |
| 36 | 518918400 |
| 37 | -343976400 |
| 38 | 99236556 |
| 39 | -16275700 |
| 40 | 1659889 |
| 41 | -107800 |
| 42 | 4354 |
| 43 | -100 |
| 44 | 1 |